feat(eslint-plugin): [naming-convention] allow selecting only const…

… variables (#2291)

packages/eslint-plugin/docs/rules/naming-convention.md

@@ -192,7 +192,7 @@ There are two types of selectors, individual selectors, and grouped selectors.
 Individual Selectors match specific, well-defined sets. There is no overlap between each of the individual selectors.
 
 - `variable` - matches any `var` / `let` / `const` variable name.
-  - Allowed `modifiers`: none.
+  - Allowed `modifiers`: `const`.
   - Allowed `types`: `boolean`, `string`, `number`, `function`, `array`.
 - `function` - matches any named function declaration or named function expression.
   - Allowed `modifiers`: none.
@@ -309,6 +309,21 @@ Group Selectors are provided for convenience, and essentially bundle up sets of
 }
 ```
 
+### Enforce that all const variables are in UPPER_CASE
+
+```json
+{
+  "@typescript-eslint/naming-convention": [
+    "error",
+    {
+      "selector": "variable",
+      "modifiers": ["const"],
+      "format": ["UPPER_CASE"]
+    }
+  ]
+}
+```
+
 ### Enforce that type parameters (generics) are prefixed with `T`
 
 This allows you to emulate the old `generic-type-naming` rule.

packages/eslint-plugin/src/rules/naming-convention.ts

@@ -80,12 +80,13 @@ type MetaSelectorsString = keyof typeof MetaSelectors;
 type IndividualAndMetaSelectorsString = SelectorsString | MetaSelectorsString;
 
 enum Modifiers {
-  readonly = 1 << 0,
-  static = 1 << 1,
-  public = 1 << 2,
-  protected = 1 << 3,
-  private = 1 << 4,
-  abstract = 1 << 5,
+  const = 1 << 0,
+  readonly = 1 << 1,
+  static = 1 << 2,
+  public = 1 << 3,
+  protected = 1 << 4,
+  private = 1 << 5,
+  abstract = 1 << 6,
 }
 type ModifiersString = keyof typeof Modifiers;
 
@@ -255,7 +256,7 @@ const SCHEMA: JSONSchema.JSONSchema4 = {
       ...selectorSchema('default', false, util.getEnumNames(Modifiers)),
 
       ...selectorSchema('variableLike', false),
-      ...selectorSchema('variable', true),
+      ...selectorSchema('variable', true, ['const']),
       ...selectorSchema('function', false),
       ...selectorSchema('parameter', true),
 
@@ -439,8 +440,18 @@ export default util.createRule<Options, MessageIds>({
         const identifiers: TSESTree.Identifier[] = [];
         getIdentifiersFromPattern(node.id, identifiers);
 
+        const modifiers = new Set<Modifiers>();
+        const parent = node.parent;
+        if (
+          parent &&
+          parent.type === AST_NODE_TYPES.VariableDeclaration &&
+          parent.kind === 'const'
+        ) {
+          modifiers.add(Modifiers.const);
+        }
+
         identifiers.forEach(i => {
-          validator(i);
+          validator(i, modifiers);
         });
       },
 

packages/eslint-plugin/tests/rules/naming-convention.test.ts

@@ -626,6 +626,10 @@ ruleTester.run('naming-convention', rule, {
     },
     {
       code: `
+        declare const ANY_UPPER_CASE: any;
+        declare const ANY_UPPER_CASE: any | null;
+        declare const ANY_UPPER_CASE: any | null | undefined;
+
         declare const string_camelCase: string;
         declare const string_camelCase: string | null;
         declare const string_camelCase: string | null | undefined;
@@ -647,6 +651,12 @@ ruleTester.run('naming-convention', rule, {
       `,
       parserOptions,
       options: [
+        {
+          selector: 'variable',
+          modifiers: ['const'],
+          format: ['UPPER_CASE'],
+          prefix: ['ANY_'],
+        },
         {
           selector: 'variable',
           types: ['string'],
@@ -824,6 +834,10 @@ ruleTester.run('naming-convention', rule, {
     },
     {
       code: `
+        declare const any_camelCase01: any;
+        declare const any_camelCase02: any | null;
+        declare const any_camelCase03: any | null | undefined;
+
         declare const string_camelCase01: string;
         declare const string_camelCase02: string | null;
         declare const string_camelCase03: string | null | undefined;
@@ -844,6 +858,12 @@ ruleTester.run('naming-convention', rule, {
         declare const boolean_camelCase16: true | false | null | undefined;
       `,
       options: [
+        {
+          selector: 'variable',
+          modifiers: ['const'],
+          format: ['UPPER_CASE'],
+          prefix: ['any_'],
+        },
         {
           selector: 'variable',
           types: ['string'],
@@ -864,7 +884,7 @@ ruleTester.run('naming-convention', rule, {
         },
       ],
       parserOptions,
-      errors: Array(16).fill({ messageId: 'doesNotMatchFormatTrimmed' }),
+      errors: Array(19).fill({ messageId: 'doesNotMatchFormatTrimmed' }),
     },
     {
       code: `